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The main change is to use only a single transfer and thus avoid tri-stating DATx during the command phase. To control the timing, we put the first word "manually" into the FIFO, wait until it has been sent on the bus, and only then DMA the rest.
Ben Blinkenlights ================= This is an umbrella project for various items related to using the 8:10 card slot of the Ben Nanonote. The "flagship" sub-project is no longer the top-level LED board but the Universal Breakout Board, in ubb/ . The original blinkenlights, a board with a line of LEDs cam/ Outline of the board; obsolete ext/ UBB variant with ground between signals; obsolete ioscript/ GPIO test pattern generator; experimental libubb/ Helper functions for accessing UBB lpc111x-isp/ In-system programmer for NXP LPC111x MCUs nxuart/ Card with ATmega48 in UART configuration; incomplete swuart-chat/ Software-implemented UART (on UBB) ubb-jtag/ JTAG via UBB (example for Milkymist One) ubb-usb/ Design for hypothetical UBB-based USB host ubb-vga/ VGA output using UBB and minimal circuitry ubbctl/ Set and query UBB signals from the command line ubb/ The Universal Breakout Board (UBB) Blinkenlights ------------- This project is a proof of concept implementation of Rikard Lindstrom's idea of using the Ben's 8:10 card slot as a general extension interface also for devices that don't speak MMC or SD/SDIO. The application is a simple LED circuit, as suggested by David Samblas. The 8:10 card slot gives access to six GPIOs, a 3.3 V supply that can be switched on and off by software, and ground. We use a simple form of multiplexing to drive ten LEDs with this interface. Note that one should only light one LED at a time. If multiple LEDs are lit, they will share the current though the common resistor, and will thus be less bright than a single LED.